Top Description Methods
org.apache.derby.mbeans

public Interface CacheManagerMBean

Known Direct Implementers
org.apache.derby.impl.services.cache.ConcurrentCacheMBeanImpl

This is an MBean that provides information about one of Derby's cache managers.

Method Summary

Modifier and TypeMethod and Description
public long

Returns:

the number of entries in the cache
getAllocatedEntries
()

Get the number of entries currently allocated in the cache.

public boolean

Returns:

true if access counts are enabled, false otherwise
getCollectAccessCounts
()

Check if collection of cache access counts is enabled.

public long

Returns:

the number of evicted objects
getEvictionCount
()

Get the number of cached objects that have been evicted from the cache in order to make room for other objects.

public long

Returns:

the number of cache hits
getHitCount
()

Get the number of cache accesses where the requested object was already in the cache.

public long

Returns:

the maximum number of entries in the cache
getMaxEntries
()

Get the maximum number of entries that could be held by this cache.

public long

Returns:

the number of cache misses
getMissCount
()

Get the number of cache accesses where the requested object was not already in the cache.

public long

Returns:

the number of objects in the cache
getUsedEntries
()

Get the number of objects that are currently in the cache.

public void
setCollectAccessCounts(boolean
true if access counts should be collected, or false otherwise
collect
)

Enable or disable collection of cache access counts.

Method Detail

getAllocatedEntriesback to summary
public long getAllocatedEntries()

Get the number of entries currently allocated in the cache. This number includes entries for objects that have been removed from the cache, whose entries have not yet been reused for other objects.

Returns:long

the number of entries in the cache

getCollectAccessCountsback to summary
public boolean getCollectAccessCounts()

Check if collection of cache access counts is enabled.

Returns:boolean

true if access counts are enabled, false otherwise

See Also
setCollectAccessCounts(boolean)
getEvictionCountback to summary
public long getEvictionCount()

Get the number of cached objects that have been evicted from the cache in order to make room for other objects.

Returns:long

the number of evicted objects

getHitCountback to summary
public long getHitCount()

Get the number of cache accesses where the requested object was already in the cache.

Returns:long

the number of cache hits

getMaxEntriesback to summary
public long getMaxEntries()

Get the maximum number of entries that could be held by this cache.

Returns:long

the maximum number of entries in the cache

getMissCountback to summary
public long getMissCount()

Get the number of cache accesses where the requested object was not already in the cache.

Returns:long

the number of cache misses

getUsedEntriesback to summary
public long getUsedEntries()

Get the number of objects that are currently in the cache.

Returns:long

the number of objects in the cache

setCollectAccessCountsback to summary
public void setCollectAccessCounts(boolean collect)

Enable or disable collection of cache access counts. That is, whether or not each hit, miss and eviction should be counted. Enabling it might impose a small overhead on cache accesses, and might reduce the system performance. Access counts are disabled by default.

Parameters
collect:boolean

true if access counts should be collected, or false otherwise

See Also
getCollectAccessCounts(), getHitCount(), getMissCount(), getEvictionCount()